<?php
$marks = 56;

if($marks >= 75) {
  echo "HNS";
}

if($marks < 75 && $marks >= 60) {
  echo "FIRST";
}

if($marks < 60 && $marks >= 50) {
  echo "SECOND";
}

if($marks < 50 && $marks >= 40) {
  echo "THIRD";
}

if($marks < 40 ) {
  echo "FAIL";
}
